Square Footage Calculator
Calculate total area for home renovations, flooring, painting, or auto projects.
Knowing the square footage of a room, house, wall, floor, or other space can be useful for many everyday projects. You may need to know the area before buying flooring, carpet, tiles, paint, furniture, or other materials.
Our square footage calculator makes this calculation simple. Enter the measurements of your space, and you can quickly find the area in square feet.
For a simple rectangular space, the main formula is easy:
Square Feet = Length × Width
For example, if a room is 12 feet long and 10 feet wide:
12 × 10 = 120 square feet
This guide explains how square footage works, how to measure a room, how to calculate odd-shaped spaces, and how to convert square feet into other units.
What Is Square Footage?
Square footage is a way to measure the area of a flat space. It tells you how much surface area a room, floor, wall, yard, or other space covers.
One square foot is a square that is 1 foot long and 1 foot wide. It is written as sq ft, square feet, or ft².
Square footage is commonly used for rooms, homes, apartments, offices, floors, walls, garages, land, and many home improvement projects.
For example:
| Length | Width | Square Footage |
|---|---|---|
| 10 ft | 10 ft | 100 sq ft |
| 10 ft | 12 ft | 120 sq ft |
| 12 ft | 12 ft | 144 sq ft |
| 15 ft | 10 ft | 150 sq ft |
| 20 ft | 15 ft | 300 sq ft |
| 20 ft | 20 ft | 400 sq ft |
The easiest way to calculate a rectangular area is to multiply the length by the width.
How Does a Square Footage Calculator Work?
A square footage calculator uses area formulas to calculate the size of a space.
For a normal rectangle or room, the calculator uses:
Area = Length × Width
You enter the length and width of your space. The calculator multiplies the two numbers and gives you the total area.
For example, imagine your bedroom is:
- Length = 14 feet
- Width = 11 feet
The calculation is:
14 × 11 = 154 square feet
So, the room has 154 sq ft of floor area.
A calculator is useful because it saves time and reduces simple calculation mistakes. It can also be helpful when your measurements are in different units or when you need to calculate several areas.
Square Footage Formula
The basic square footage formula is:
Square Feet = Length × Width
Both measurements should be in the same unit before you multiply them.
For example:
16 ft × 12 ft = 192 sq ft
The answer is 192 square feet.
If you measure in inches, you need to convert the measurements before using the formula. There are 12 inches in one foot and 144 square inches in one square foot.
Example
Suppose a room is 10 feet long and 13 feet wide.
10 × 13 = 130
The room is 130 square feet.
This simple formula works for most rectangular rooms.
How to Calculate Square Feet of a Room
Calculating the square footage of a rectangular room is easy.
First, measure the room from one wall to the opposite wall to find the length. Then measure the other direction to find the width.
Try to measure carefully and write down both measurements.
Next, multiply the length by the width.
Example: 12 × 10 Room
Suppose your room measures:
- Length: 12 ft
- Width: 10 ft
Use the formula:
12 × 10 = 120 sq ft
The room has 120 square feet.
If your room has an unusual shape, you may need to divide it into smaller rectangles or other simple shapes and calculate each section separately.
How to Measure a Room for Square Footage
You do not need special equipment to measure a simple room. A tape measure, pencil, and paper are usually enough.
Follow these steps:
- Measure the length of the room.
- Measure the width of the room.
- Make sure both measurements use the same unit.
- Multiply length by width.
- Write down the final square footage.
For better accuracy, measure from wall to wall at floor level.
If the room is not a perfect rectangle, make a simple drawing and divide the room into smaller sections.
Measurement Example
Imagine you measure a room and get:
Length = 15 ft
Width = 12 ft
Now calculate:
15 × 12 = 180 sq ft
Your room is approximately 180 square feet.
How to Calculate Square Footage of an L-Shaped Room
An L-shaped room cannot be calculated correctly by simply multiplying its longest length by its widest width because that would include an area that is not part of the room.
The simple solution is to divide the room into two or more rectangles.
For example:
| Section | Length | Width | Area |
|---|---|---|---|
| Section A | 12 ft | 10 ft | 120 sq ft |
| Section B | 6 ft | 8 ft | 48 sq ft |
| Total | 168 sq ft |
Add the two areas:
120 + 48 = 168 sq ft
The total room area is 168 square feet.
This method works for many irregular rooms. Break the space into simple shapes, calculate each part, and then add the results.
How to Calculate Square Footage of an Irregular Shape
Not every space is a simple rectangle. A room may have a corner, extension, bay window, closet, or another unusual section.
You can still calculate the area.
Start by dividing the space into shapes that are easier to measure. Rectangles and squares are usually the easiest.
Calculate each section separately and then add the results.
Example
Imagine a space has three sections:
- Section 1 = 100 sq ft
- Section 2 = 50 sq ft
- Section 3 = 25 sq ft
Add them:
100 + 50 + 25 = 175 sq ft
The total area is 175 square feet.
For circles and triangles, use the appropriate area formula rather than the rectangle formula.
Square Footage Formulas for Common Shapes
Different shapes need different formulas.
| Shape | Formula |
|---|---|
| Square | Side × Side |
| Rectangle | Length × Width |
| Triangle | Base × Height ÷ 2 |
| Circle | π × Radius² |
| Trapezoid | (Base 1 + Base 2) × Height ÷ 2 |
For a square, both sides have the same length.
For a rectangle, multiply the long side by the short side.
For a triangle, multiply the base by the height and divide the answer by 2.
For a circle, use the radius and π.
Using the correct formula is important when the space is not rectangular.
How to Calculate Square Footage From Feet and Inches
Sometimes a tape measure gives you a measurement such as 12 feet 6 inches.
You should convert the inches into feet before multiplying.
There are 12 inches in 1 foot.
So:
6 inches ÷ 12 = 0.5 feet
Therefore:
12 feet 6 inches = 12.5 feet
Now you can use the square footage formula.
For example:
12.5 × 10 = 125 sq ft
So a room that is 12 feet 6 inches long and 10 feet wide has 125 square feet.
A calculator that accepts feet and inches can make this process easier.
How to Calculate Square Feet From Inches
If both measurements are in inches, you can calculate the area in square inches first.
Then convert square inches to square feet.
There are:
144 square inches = 1 square foot
So:
Square Feet = Square Inches ÷ 144
For example, suppose an area is 120 inches long and 96 inches wide.
First calculate:
120 × 96 = 11,520 square inches
Then:
11,520 ÷ 144 = 80 square feet
The area is 80 sq ft.
Square Feet to Square Meters
Square feet and square meters are both units of area.
To convert square feet to square meters:
Square meters = Square feet × 0.092903
For example:
100 sq ft × 0.092903 = 9.29 m²
So:
100 square feet ≈ 9.29 square meters
To convert square meters to square feet:
Square feet = Square meters × 10.7639
For example:
20 m² × 10.7639 = 215.28 sq ft
Common conversions include:
| Square Feet | Approx. Square Meters |
|---|---|
| 50 sq ft | 4.65 m² |
| 100 sq ft | 9.29 m² |
| 150 sq ft | 13.94 m² |
| 200 sq ft | 18.58 m² |
| 500 sq ft | 46.45 m² |
| 1,000 sq ft | 92.90 m² |
These conversion values are useful when working with plans, property information, or materials that use metric measurements.
Square Feet to Square Yards
Square yards are another common area measurement.
There are 9 square feet in 1 square yard.
Therefore:
Square Yards = Square Feet ÷ 9
For example:
180 sq ft ÷ 9 = 20 square yards
So 180 square feet is equal to 20 square yards.
To convert square yards to square feet:
Square Feet = Square Yards × 9
How to Calculate the Square Footage of a House
To estimate the total floor area of a house, calculate each room or section separately and then add the results.
For example:
| Area | Square Feet |
|---|---|
| Living room | 250 |
| Kitchen | 150 |
| Bedroom 1 | 140 |
| Bedroom 2 | 130 |
| Bedroom 3 | 120 |
| Hallways | 100 |
| Total | 890 sq ft |
The total is:
250 + 150 + 140 + 130 + 120 + 100 = 890 sq ft
The exact definition of a property’s reported square footage can depend on the purpose and local measurement standards, so a calculator result should not automatically be treated as an official real-estate measurement.
How to Calculate Square Footage for Flooring
Square footage is especially useful when buying flooring.
First, calculate the floor area.
For example:
Room length = 15 ft
Room width = 12 ft
15 × 12 = 180 sq ft
That gives you 180 square feet of floor area.
However, flooring projects often need extra material for cuts, mistakes, damaged pieces, and installation waste. A common planning approach is to purchase additional material rather than ordering exactly the calculated floor area. The amount of extra material depends on the flooring type and installation pattern.
Example With 10% Extra
Room area:
180 sq ft
Extra material:
180 × 10% = 18 sq ft
Total:
180 + 18 = 198 sq ft
So you would plan for approximately 198 square feet of flooring, subject to the manufacturer’s recommendations.
How to Calculate Square Footage for Paint
Square footage can also help when estimating wall coverage.
For a simple wall:
Wall Area = Width × Height
For example:
15 ft × 9 ft = 135 sq ft
The wall has 135 square feet of surface area.
If the wall has a large door or window, you can calculate its area and subtract it from the wall area.
For example:
Wall = 135 sq ft
Window = 20 sq ft
135 − 20 = 115 sq ft
The remaining area is 115 square feet.
Paint coverage depends on the product, surface, number of coats, and application method, so use the paint manufacturer’s coverage information when buying paint.
How to Calculate Square Footage for a Wall
To calculate the area of a rectangular wall, multiply its width by its height.
Wall Square Feet = Width × Height
Example:
- Wall width = 20 ft
- Wall height = 8 ft
20 × 8 = 160 sq ft
The wall has 160 square feet.
If there are doors or windows, calculate those areas separately and subtract them when you need the net surface area.
How to Calculate Square Footage of Land
For a rectangular piece of land, the basic formula is still:
Length × Width
For example:
100 ft × 50 ft = 5,000 sq ft
So the land area is 5,000 square feet.
Irregular land is more difficult. You may need to divide the property into several rectangles, triangles, or other shapes and add their areas.
For property boundaries or legal measurements, use an appropriate professional survey rather than relying only on a basic calculator.
Common Room Sizes and Square Feet
The following examples can help you understand how room dimensions translate into square footage.
| Room Dimensions | Square Feet |
|---|---|
| 8 × 10 ft | 80 sq ft |
| 9 × 10 ft | 90 sq ft |
| 10 × 10 ft | 100 sq ft |
| 10 × 12 ft | 120 sq ft |
| 12 × 12 ft | 144 sq ft |
| 12 × 15 ft | 180 sq ft |
| 15 × 15 ft | 225 sq ft |
| 15 × 20 ft | 300 sq ft |
| 20 × 20 ft | 400 sq ft |
These are simply length × width calculations. For example, a 12 × 12 room has 144 square feet.
Common Square Footage Calculation Mistakes
Square footage calculations are simple, but small measurement mistakes can change the final answer.
Using Different Units
Do not multiply feet by inches without converting first.
For example, if the length is in feet and the width is in inches, convert the width to feet first.
Forgetting Irregular Areas
Do not treat an L-shaped room as one large rectangle if part of that rectangle is outside the actual room.
Break the room into smaller sections.
Measuring Incorrectly
Measure carefully from wall to wall. If the room has unusual corners, take multiple measurements.
Rounding Too Early
Keep your measurements as accurate as possible during the calculation. Round the final result when appropriate.
Ordering Exactly the Calculated Material
The calculated square footage tells you the area. It does not always equal the amount of material you should buy.
Flooring, tile, and other materials may require additional material for cuts and waste.
Why Use a Square Footage Calculator?
A square footage calculator can save time when you need to calculate several areas.
Instead of doing every calculation by hand, you can enter your measurements and get the result quickly.
It can be useful for:
- Measuring bedrooms
- Measuring living rooms
- Planning flooring
- Estimating carpet
- Planning tile
- Estimating wall area
- Planning paint
- Comparing room sizes
- Measuring garages
- Estimating land area
- Planning home improvement projects
- Converting area units
For simple calculations, the basic formula is enough. For multiple rooms or different units, a calculator can make the process easier.
Important Points to Remember
Keep these points in mind when calculating square footage:
- Square feet measure area, not length.
- Use length × width for a rectangular space.
- Keep both measurements in the same unit.
- Convert inches to feet before multiplying when needed.
- Divide irregular spaces into smaller shapes.
- Add the areas of all sections for the total.
- Use the correct formula for circles and triangles.
- Add extra material when a project requires waste allowance.
- Check manufacturer instructions before purchasing materials.
- For official property measurements, follow the applicable local standards.
Quick Square Footage Examples
Here are some quick examples.
Example 1:
10 ft × 10 ft = 100 sq ft
Example 2:
12 ft × 15 ft = 180 sq ft
Example 3:
20 ft × 10 ft = 200 sq ft
Example 4:
16 ft × 14 ft = 224 sq ft
Example 5:
25 ft × 20 ft = 500 sq ft
The same basic formula works for each rectangular space:
Length × Width = Square Feet
Frequently Asked Questions About Square Footage
How do I calculate square footage?
Measure the length and width of the space in the same unit and multiply them.
Square Feet = Length × Width
For example, a 12 ft × 10 ft room is 120 square feet.
What is the square footage of a 12 by 12 room?
A 12 ft × 12 ft room has:
12 × 12 = 144 sq ft
So the room is 144 square feet.
How do I calculate square footage of an L-shaped room?
Divide the L-shaped room into two or more rectangles. Calculate the square footage of each rectangle and add the results together. This avoids counting areas that are not actually part of the room.
How many square feet are in one square meter?
One square meter is approximately 10.7639 square feet.
To convert square meters to square feet, multiply the square meters by 10.7639.
How many square feet are in an acre?
One acre contains 43,560 square feet.
To convert acres to square feet, multiply the number of acres by 43,560.
Do I need to add extra square footage for flooring?
Usually, you should plan for some extra material because flooring may require cuts and can produce waste. The exact amount depends on the product, room shape, installation pattern, and manufacturer’s guidance.
Can I calculate square footage from inches?
Yes. You can convert the measurements to feet first or calculate the area in square inches and divide by 144.
Can I calculate the square footage of a house?
Yes. Measure each relevant room or area, calculate its square footage, and add the areas together. However, official property square footage may follow specific measurement standards.
Conclusion
Calculating square footage does not have to be difficult. For a simple rectangular room or space, all you need is the length and width.
The main formula is:
Square Feet = Length × Width
If the space has an unusual shape, divide it into smaller sections and calculate each section separately. Then add the areas together.
A square footage calculator can make this process faster and easier, especially when you have multiple rooms, feet and inches, or different measurement units.
Whether you are planning flooring, measuring a room, estimating paint coverage, checking a property size, or working on a home project, knowing the square footage gives you a useful starting point for planning and estimating.